Humidity-dependent antibacterial powdery composition, process for producing the same, humidity-dependent antibacterial food storing article and method of storing food

ABSTRACT

The humidity-dependent antibacterial powdery composition comprises a volatile oily antibacterial substance contained in a high ratio and a water-soluble film forming agent and the behavior of release of the antibacterial substance is changed depending on humidity. The process for producing the same is characterized in that a water-soluble film forming agent optionally together with a powder vehicle is dissolved and/or dispersed in water, subsequently a volatile oily antibacterial substance optionally together with an emulsifying agent is added to the solution and emulsified, and thereafter the obtained emulsion is spray dried into powder. The humidity-dependent antibacterial food storing article is characterized by carrying the humidity-dependent antibacterial powdery composition. The method of storing food is characterized in that the volatile oily antibacterial substance is released from the humidity-dependent antibacterial food storing article toward food lying in an atmosphere of 70% or higher humidity.

TECHNICAL FIELD

The present invention relates to a humidity-dependent antibacterialpowdery composition of excellent applicability wherein a volatile oilyantibacterial substance can be contained in high ratio; a process forproducing the same; a humidity-dependent antibacterial food storingarticle; and a method of storing food.

BACKGROUND ART

As a substance for preventing fungal outbreak or bacterial growth infood, a volatile oily antibacterial substance such as an isothiocyanateester represented by allyl isothiocyanate is known. However, since thevolatility of the substance is high, it has a characteristic that itseffect is decreased in an extremely short time. Therefore, it has aproblem in the duration of the effect itself. Accordingly, as one of themeans of solving such a problem, a method of forming ahumidity-dependent antibacterial powdery composition by enclosing avolatile oily antibacterial substance in a cyclodextrin so as to releasethe substance only in a high humid atmosphere and employing thecomposition has been proposed (see, for example, Japanese Patent No.2,790,772). If a volatile oily antibacterial substance is enclosed in acyclodextrin, chemical stability, deodorization, antioxidation,photodegradation inhibition, etc. of the substance can be attained,therefore, this method is an excellent method. However, since at mostonly an equivalent molar amount of volatile oily antibacterial substanceis enclosed in the cyclodextrin, the ratio of the substance contained inthe antibacterial powdery composition is at most only about 10% byweight. In addition, this antibacterial powdery composition is difficultto release the volatile oily antibacterial substance unless it is in anatmosphere of 90% or higher humidity, therefore, there remains room forimprovement in the applicability.

It is therefore an object of the present invention to provide ahumidity-dependent antibacterial powdery composition of excellentapplicability wherein a volatile oily antibacterial substance can becontained in high ratio; a process for producing the same; ahumidity-dependent antibacterial food storing article; and a method ofstoring food.

DISCLOSURE OF THE INVENTION

The present invention has been accomplished in view of the foregoingmatters, according to a first aspect and feature of the presentinvention, there is provided a humidity-dependent antibacterial powderycomposition characterized in that it comprises a volatile oilyantibacterial substance and a water-soluble film forming agent and thebehavior of release of the antibacterial substance is changed dependingon humidity.

According to a second aspect and feature of the present invention, inaddition to the first feature, the volatile oily antibacterial substanceis an isothiocyanate ester.

According to a third aspect and feature of the present invention, inaddition to the first feature, the water-soluble film forming agent isgum arabic.

According to a fourth aspect and feature of the present invention, inaddition to the first feature, the composition further comprises apowder vehicle.

According to a fifth aspect and feature of the present invention, inaddition to the first feature, the composition shows the behavior ofrelease wherein the releasing ratio of the volatile oily antibacterialsubstance at 100% humidity is 1.5 times or more than the releasing ratioof the volatile oily antibacterial substance at 75% humidity.

According to a sixth aspect and feature of the present invention, thereis provided a process for producing a humidity-dependent antibacterialpowdery composition, in which the behavior of release of a volatile oilyantibacterial substance is changed depending on humidity characterizedin that a water-soluble film forming agent optionally together with apowder vehicle is dissolved and/or dispersed in water, subsequently avolatile oily antibacterial substance optionally together with anemulsifying agent is added to the solution and emulsified, andthereafter the obtained emulsion is spray dried into powder.

According to a seventh aspect and feature of the present invention,there is provided a humidity-dependent antibacterial food storingarticle characterized by carrying a humidity-dependent antibacterialpowdery composition according to the first feature.

According to an eighth aspect and feature of the present invention,there is provided a method of storing food characterized in that avolatile oily antibacterial substance is released from ahumidity-dependent antibacterial food storing article according to theseventh feature toward food lying in an atmosphere of 70% or higherhumidity.

BEST MODE FOR CARRYING OUT THE INVENTION

The humidity-dependent antibacterial powdery composition of the presentinvention is characterized in that it comprises a volatile oilyantibacterial substance and a water-soluble film forming agent and thebehavior of release of the antibacterial substance is changed dependingon humidity, wherein the volatile oily antibacterial substance can becontained in high ratio. In addition, the humidity-dependentantibacterial powdery composition of the present invention hardlyreleases the volatile oily antibacterial substance in an atmosphere ofabout 60% humidity. However, when it is in an atmosphere of 70% orhigher humidity, in which fungi can grow, the volatile oilyantibacterial substance will be released, therefore, the composition isexcellent in applicability.

The volatile oily antibacterial substance in the humidity-dependentantibacterial powdery composition of the present invention means an oilysubstance having volatility at normal temperature and exerting anantibacterial effect. For example, an isothiocyanate ester, which is thepungent component of mustard or Japanese horseradish, a monoterpenecompound, which is abundantly contained in natural plants, etc.correspond to this. These are natural products obtained from a plantextract or the like, and their safety to the human body is high. Inparticular, the isothiocyanate ester exerts an excellent antibacterialeffect, therefore, it is preferably employed in food hygiene.Incidentally, the volatile oily antibacterial substance is not limitedto a natural product but may be a synthetic product synthesized by aknown method per se.

Specific examples of the isothiocyanate ester include allylisothiocyanate, phenyl isothiocyanate, methyl isothiocyanate, ethylisothiocyanate, propyl isothiocyanate, isopropyl isothiocyanate, butylisothiocyanate, isobutyl isothiocyanate, isoamyl isothiocyanate, benzylisothiocyanate, cyclohexyl isothiocyanate and the like.

Examples of the monoterpene compound include terpene hydrocarbons,terpene alcohols, terpene aldehydes, terpene ketones, terpene oxides andthe like.

The water-soluble film forming agent in the humidity-dependentantibacterial powdery composition of the present invention means the onehaving a property of forming a film when its aqueous solution is dried.The water-soluble film forming agent may be any as long as itconstitutes a capsule particle with hygroscopicity, in which thevolatile oily antibacterial substance is enclosed, and can release thesubstance in an atmosphere of a certain humidity or higher. Specificexamples thereof include gum arabic, gelatins, hemicelluloses,microbially produced polysaccharides, modified starches and the like.These may be used alone or by combining with two or more kinds. It isknown that a water-soluble film forming agent can be used as aconstituent of a solid phase in the state of fine particles containing awater-soluble active substance, etc. for dispersing the solid phase inan oil phase (see, for example, JP-A-2000-157168). However, a method ofutilizing a water-soluble film forming agent, in which a hygroscopiccapsule particle is constituted by the water-soluble film forming agent,whereby a volatile oily antibacterial substance is enclosed, and theenclosed volatile oily antibacterial substance is released outside asthe capsule particle absorbs moisture is a new method, which has notbeen known so far.

The humidity-dependent antibacterial powdery composition of the presentinvention can be produced by, for example, dissolving and/or dispersinga water-soluble film forming agent optionally together with a powdervehicle in water, subsequently adding a volatile oily antibacterialsubstance optionally together with an emulsifying agent to the solutionand performing an emulsifying treatment, and thereafter spray drying theobtained emulsion into powder.

The powder vehicle, in the case where a substance, which hashygroscopicity even in an atmosphere of about 70% humidity such as gumarabic, is used as a water-soluble film forming agent, effectivelyfunctions for securing the stability of releasing the volatile oilyantibacterial substance by maintaining the capsule particles constitutedby the water-soluble film forming agent in the dispersed state withoutclumping together in the powdery composition. Specific examples of thepowder vehicle include starches, starch decomposition products,dextrins, monosaccharides such as glucose, disaccharides such as lactoseand the like. These may be used alone or by combining with two or morekinds. Preferred examples of the powder vehicle include nonhygroscopicstarches, dextrins and the like.

The emulsifying agent effectively functions in the case where anemulsion is prepared by using, as a water-soluble film forming agent, asubstance other than a substance having an emulsifying action such asgum arabic or Capsul (brand name, manufactured by National Starch andChemical Co. U.S., a modified starch available from Nippon NSC Ltd. inJapan). Specific examples of the emulsifying agent include polyglycerolfatty acid esters, sucrose fatty acid esters, sorbitan fatty acid estersand the like. These may be used alone or by combining with two or morekinds.

The emulsifying treatment for preparing the emulsion may be carried outin accordance with the conventional methods. It is preferred that thespray drying of the emulsion is carried out at 140 to 180° C. When thetemperature is lower than 140° C., dried powder may not be obtainedbecause the moisture cannot be sufficiently evaporated. On the otherhand, the temperature is higher than 180° C., the volatile oilyantibacterial substance may be volatilized in the process.

Incidentally, after the water-soluble film forming agent optionallytogether with the powder vehicle is dissolved and/or dispersed in water,the step of adding the volatile oily antibacterial substance optionallytogether with the emulsifying agent to the solution may be carried outat normal temperature. However, after the water-soluble film formingagent optionally together with the powder vehicle is dissolved and/ordispersed in water at normal temperature, the solution may be heated toabout 60 to 80° C. once, or the water-soluble film forming agentoptionally together with the powder vehicle is dissolved and/ordispersed in water while heating to about 60 to 80° C. from thebeginning, whereby the solubility of the water-soluble film formingagent is increased or the solution is sterilized by heating, andsubsequently the solution is cooled down to room temperature to about60° C., then the volatile oily antibacterial substance optionallytogether with the emulsifying agent may be added. In addition, thevolatile oily antibacterial substance may be added after dissolving itin an edible oil and fat such as a medium chain fatty acid representedby a purified palm oil.

The humidity-dependent antibacterial powdery composition of the presentinvention produced as above mainly consists of an aggregate ofhygroscopic spherical-shaped capsule particles with an average particlesize of 1 to 200 μm enclosing the volatile oily antibacterial substance,contains the volatile oily antibacterial substance in high ratio (forexample, a composition in which the ratio of the contained volatile oilyantibacterial substance is 11 to 20% by weight), and further, therelease stability thereof is secured. The humidity-dependentantibacterial powdery composition of the present invention may be usedin the form as it is, however, it may be used in the form of ahumidity-dependent antibacterial food storing article by carrying thecomposition on a variety of food storing articles such as syntheticresin film, nonwoven fabric, paper, tray, sheet, bags, containers andtape by a method such as coating or mixing. In order to make thehumidity-dependent antibacterial powdery composition of the presentinvention be the one to be uniformly carried on the food storing articleand be the one stably releasing the volatile oily antibacterialsubstance from the carried powdery composition, the blending ratio ofthe volatile oily antibacterial substance and the water-soluble filmforming agent in the humidity-dependent antibacterial powderycomposition is preferably 0.5 to 20 parts by weight, more preferably 1to 7 parts by weight of the water-soluble film forming agent relative to1 part by weight of the volatile oily antibacterial substance. Inaddition, in the case where the powder vehicle is used, the blendingratio thereof is preferably 0.5 to 100 parts by weight, more preferably0.7 to 20 parts by weight relative to 1 part by weight of the total ofthe volatile oily antibacterial substance and the water-soluble filmforming agent. Incidentally, the average particle size of the capsuleparticles is preferably 2 to 150 μm, more preferably 5 to 100 μm, andfurther more preferably 11 to 50 μm. When the average particle size istoo small, the amount of the enclosed volatile oily antibacterialsubstance may be small. On the other hand, when it is too large, it maybe difficult to carry the composition on the food storing article.

EXAMPLES

The humidity-dependent antibacterial powdery composition of the presentinvention will be described in more detail with reference to Examples,however, the present invention is not to be construed as being limitedto the following description.

Example 1 Production of Humidity-dependent Antibacterial PowderyComposition and Property Thereof (Part 1)

At 60° C., 250 g of gum arabic as a water-soluble film forming agent and250 g of starch and 300 g of dextrin as a powder vehicle were added to1500 g of water and mixed and stirred. After the solution was cooleddown to room temperature, 200 g of allyl isothiocyanate as a volatileoily antibacterial substance was added and an emulsifying treatment wascarried out with an emulsifier (TK Homo mixer, Tokushu Kika Kogyo),whereby an emulsion was obtained. The obtained emulsion was spray driedwith a spray dryer (drying temperature: 150° C.), whereby a lightcream-colored powdery composition was obtained. The ratio of allylisothiocyanate contained in this powdery composition was 13.8% byweight. The obtained powdery composition was observed with a microscopeand it was found that this powdery composition mainly consists of anaggregate of spherical-shaped capsule particles. The average particlesize of the capsule particles was measured and found to be 50 μm. Theirritating smell of allyl isothiocyanate was hardly detected from theobtained powdery composition. Although the irritating smell of allylisothiocyanate was hardly detected from this powdery composition in anatmosphere of about 60% humidity, the irritating smell of allylisothiocyanate could be detected in an atmosphere of about 80% humidity.This revealed that this powdery composition releases allylisothiocyanate depening on humidity.

Experimental Example 1

1-1: Production of Antibacterial Sheet Carrying Humidity-dependentAntibacterial Powdery Composition

Two percent by weight of the humidity-dependent antibacterial powderycomposition produced in Example 1 was uniformly mixed in an acrylicbinder. The obtained mixture was applied on one surface of nonwovenfabric using a roller and the applied surface was pressed to dry usingan iron heated at 120° C., thus an antibacterial sheet in which thehumidity-dependent antibacterial powdery composition was uniformlydispersed and mixed in the coating film was produced.

1-2: Antibacterial Effect of Antibacterial Sheet

A desoxycholate agar was poured in a petri dish and solidified, and thenE. coli suspension was applied on its surface. This petri dish in astate of being uncovered with a lid was put in a sealed container of 37°C. in temperature and 100% in humidity, then the growth of E. coli wasobserved grossly. At this time, the one in which the antibacterial sheet(16×10 cm) produced as above was put in the sealed container togetherwith the petri dish was defined as a test group, and the one without anantibacterial sheet was defined as a control group. The results areshown in Table 1. As is clear from Table 1, because allyl isothiocyanatewas released effectively in the container from the antibacterial sheetin the test group, an excellent antibacterial effect was observed.

TABLE 1 24 hours 48 hours 72 hours Test group − − + Control group ++ ++++ −; no growth of bacteria / +; slight growth of bacteria / ++;apparent growth of bacteria

Experimental Example 2

2-1: Production of Antibacterial Polyethylene Bag CarryingHumidity-dependent Antibacterial Powdery Composition

A master batch was produced by uniformly mixing 20% by weight of thehumidity-dependent antibacterial powdery composition produced in Example1 in a polyethylene resin. Five percent by weight of this mater batchwas uniformly mixed in a polyethylene resin and the obtained mixture wassubjected to an inflation process and an antibacterial polyethylene bag(20×30 cm) of 60 μm in thickness in which the humidity-dependentantibacterial powdery composition was uniformly dispersed and mixed wasproduced.

2-2: Antibacterial Effect of Antibacterial Polyethylene Bag

As for a test group, 200 g of freshly prepared rice-cake was put in theantibacterial polyethylene bag produced as above, and the bag washeat-sealed and stored at 20° C. and the growth of fungi was observedgrossly. In addition, as for a control group, 200 g of freshly preparedrice-cake was put in a polyethylene bag (20×30 cm) of 60 μm in thicknessin which the humidity-dependent antibacterial powdery composition wasnot dispersed or mixed, and the bag was heat-sealed and stored at 20° C.and the growth of fungi was observed grossly. The results are shown inTable 2. As is clear from Table 2, because allyl isothiocyanate wasreleased effectively in the antibacterial polyethylene bag from the bagin the test group, an excellent antibacterial effect was observed.Incidentally, the humidity inside the bag was about 100%.

TABLE 2 1 week 2 weeks 3 weeks Test group − − − Control group + ++ ++ −;no growth of fungi / +; slight growth of fungi / ++; apparent growth offungi2-3: Production of Antibacterial Multilayer Synthetic Resin Bag CarryingHumidity-dependent Antibacterial Powdery Composition

A master batch was produced by uniformly mixing 20% by weight of thehumidity-dependent antibacterial powdery composition produced in Example1 in a polyethylene resin. Five percent by weight of this mater batchwas uniformly mixed in a polyethylene resin and the obtained mixture waslaminated on a polyester film by being extruded using a T die, wherebyan antibacterial multilayer synthetic resin film was produced. Using theantibacterial multilayer synthetic resin film produced as above, anantibacterial multilayer synthetic resin bag (20×30 cm) consisting of apolyethylene layer of 40 μm in thickness as the inner layer, in whichthe humidity-dependent antibacterial powdery composition was uniformlydispersed and mixed, and a polyester layer of 12 μm in thickness as theouter layer was produced. Such an antibacterial multilayer syntheticresin bag consisting of a synthetic resin layer, in which thehumidity-dependent antibacterial powdery composition is uniformlydispersed and mixed, as the inner layer and a synthetic resin layer, inwhich the humidity-dependent antibacterial powdery composition is notdispersed or mixed, as the outer layer has a release directivity inwhich the volatile oily antibacterial substance is released only insidethe bag.

Example 2 Production of Humidity-dependent Antibacterial PowderyComposition (Part 2)

At 60° C., 300 g of gum arabic and 400 g of dextrin were added to 1500 gof water and mixed and stirred. After the solution was cooled down toroom temperature, a solution obtained by dissolving 200 g of allylisothiocyanate in 100 g of purified palm oil was added. In the samemanner as in Example 1, a white-colored powdery composition mainlyconsisting of an aggregate of spherical-shaped capsule particles with anaverage particle size of 50 μm was obtained. The ratio of allylisothocyanate contained in this powdery composition was 15.8% by weight.

Example 3 Production of Humidity-dependent Antibacterial PowderyComposition (Part 3)

At 80° C., 700 g of Capsul was added to 1500 g of water and mixed andstirred. After the solution was cooled down to room temperature, asolution obtained by dissolving 150 g of allyl isothiocyanate in 150 gof purified palm oil was added. In the same manner as in Example 1, alight yellow-colored powdery composition mainly consisting of anaggregate of spherical-shaped capsule particles with an average particlesize of 50 μm was obtained. The ratio of allyl isothocyanate containedin this powdery composition was 12.5% by weight.

Example 4 Production of Humidity-dependent Antibacterial PowderyComposition (Part 4)

At 80° C., 850 g of Capsul was added to 1500 g of water and mixed andstirred. After the solution was cooled down to room temperature, 150 gof allyl isothiocyanate was added. In the same manner as in Example 1, alight yellow-colored powdery composition mainly consisting of anaggregate of spherical-shaped capsule particles with an average particlesize of 30 μm was obtained. The ratio of allyl isothocyanate containedin this powdery composition was 13.2% by weight.

Example 5 Production of Humidity-dependent Antibacterial PowderyComposition (Part 5)

At normal temperature, 700 g of gum arabic was added to 1500 g of waterand mixed and stirred. Then, a solution obtained by dissolving 200 g ofallyl isothiocyanate in 100 g of purified palm oil was added. In thesame manner as in Example 1, a white-colored powdery composition mainlyconsisting of an aggregate of spherical-shaped capsule particles with anaverage particle size of 50 μm was obtained. The ratio of allylisothocyanate contained in this powdery composition was 16.4% by weight.

Experimental Example 3

3-1: Allyl Isothiocyanate Releasing Property of Humidity-dependentAntibacterial Powdery Compositions obtained in Examples 2 to 5

The allyl isothiocyanate releasing ratios of the humidity-dependentantibacterial powdery compositions obtained in Examples 2 to 5 athumidities of 60%, 70%, 75% and 100% are shown in Table 3 together withthe releasing ratios of a known humidity-dependent antibacterial powderycomposition in which allyl isothoicyanate was enclosed in a cyclodextrin(CD inclusion: see, for example, Japanese Patent No. 2,790,772) (thereleasing ratios were calculated from the residual ratios of allylisothiocyanate in the humidity-dependent antibacterial powderycompositions after releasing). As is clear from Table 3, the release ofallyl isothiocyanate from the humidity-dependent antibacterial powderycompositions obtained in Examples 2 to 5 was observed from 70% ofhumidity in each case. The compositions show the behavior of release inwhich the releasing ratio of allyl isothiocyanate at 100% humidity is1.5 times or more than the releasing ratio of allyl isothiocyanate at75% humidity, which reveals that these are a humidity-dependentantibacterial powdery composition showing unprecedented excellentbehavior of release.

TABLE 3 Humidity-dependent antibacterial powdery composition ReleasingExample Example Example Example CD ratio (%) 2 3 4 5 inclusion 60% RH 00 0 0 0 70% RH 4.2 4.4 3.8 4.6 0 75% RH 49.8 45.1 21.2 46.2 0 100% RH 88.8 82.0 88.4 87.1 80.03-2: Heat-resistant Property of Humidity-dependent Antibacterial PowderyCompositions Obtained in Examples 2 to 5

The residual ratios of allyl isothiocyanate in the humidity-dependentantibacterial powdery compositions obtained in Examples 2 to 5 are shownin Table 4 together with the residual ratios of a knownhumidity-dependent antibacterial powdery composition in which allylisothoicyanate was enclosed in a cyclodextrin (CD inclusion: see, forexample, Japanese Patent No. 2,790,772) when the humidity-dependentantibacterial powdery compositions were heated at 180° C. As is clearfrom Table 4, the humidity-dependent antibacterial powdery compositionobtained in Example 4 was more excellent in heat-resistance than theknown humidity-dependent antibacterial powdery composition.

TABLE 4 Humidity-dependent antibacterial powdery composition ResidualExample Example Example Example CD ratio (%) 2 3 4 5 inclusion Starting100 100 100 100 100 point After 5 75.4 75.6 96.7 80.1 92.5 minutes After10 69.1 69.9 92.7 75.7 83.3 minutes After 15 64.2 67.6 90.9 73.6 75.2minutes After 20 62.7 65.4 88.4 71.8 70.4 minutes

Industrial Applicability

According to the present invention, a humidity-dependent antibacterialpowdery composition of excellent applicability wherein a volatile oilyantibacterial substance can be contained in high ratio; a process forproducing the same; a humidity-dependent antibacterial food storingarticle; and a method of storing food are provided.

1. A humidity-dependent antibacterial food storing article, the foodstoring article comprising a resin into which a humidity-dependentantibacterial powdery composition has been mixed, saidhumidity-dependent antibacterial powdery composition comprising: avolatile oily antibacterial substance and a water-soluble film formingagent, wherein the behavior of release of the antibacterial substancechanges depending on humidity, wherein said humidity-dependentantibacterial powdery composition comprises an aggregate of hygroscopicspherical-shaped capsule particles enclosing the volatile oilyantibacterial substance; said capsule particles comprise a water-solublefilm forming agent; and said volatile oily antibacterial substance is anisothiocyanate ester.
 2. The humidity-dependent antibacterial foodstoring article according to claim 1, wherein the water-soluble filmforming agent is gum arabic.
 3. The humidity-dependent antibacterialfood storing article according to claim 1, wherein the compositionfurther comprises a powder vehicle.
 4. The humidity-dependentantibacterial food storing article according to claim 1, wherein thecomposition shows the behavior of release wherein the releasing ratio ofthe volatile oily antibacterial substance at 100% humidity is 1.5 timesor more than the releasing ratio of the volatile oily antibacterialsubstance at 75% humidity.
 5. The humidity-dependent antibacterial foodstoring article according to claim 1, wherein the food storing articleis selected from the group consisting of synthetic resin film, nonwovenfabric, paper, tray, sheet, bags, containers and tape.
 6. Thehumidity-dependent antibacterial food storing article according to claim1, wherein the humidity-dependent antibacterial powdery composition isin the resin in a uniformly dispersed state.
 7. A process for producinga humidity-dependent antibacterial food storing article according toclaim 1, in which the behavior of release of a volatile oilyantibacterial substance is changed depending on humidity, characterizedin that a water-soluble film forming agent optionally together with apowder vehicle is dissolved and/or dispersed in water, subsequently avolatile oily antibacterial substance optionally together with anemulsifying agent is added to the solution and emulsified, andthereafter the obtained emulsion is spray dried into powder, and mixingthe powder composition in a resin which is formed into or coated onto anarticle.
 8. A method of storing food characterized in that a volatileoily antibacterial substance is released from a humidity-dependentantibacterial food storing article according to claim 1 toward foodlying in an atmosphere of 70% or higher humidity.
 9. Ahumidity-dependent antibacterial food storing article comprising ahumidity-dependent antibacterial powdery composition coated on the foodstoring article in a coating film, said humidity-dependent antibacterialpowdery composition comprising: a volatile oily antibacterial substanceand a water-soluble film forming agent, wherein the behavior of releaseof the antibacterial substance changes depending on humidity, whereinsaid humidity-dependent antibacterial powdery composition comprises anaggregate of hygroscopic spherical-shaped capsule particles enclosingthe volatile oily antibacterial substance; said capsule particlescomprise a water-soluble film forming agent and said volatile oilyantibacterial substance is an isothiocyanate ester.